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Playing The Odds

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It's often said that we are not training enough scientists, but I'm much more concerned that our schools aren't teaching the non-scientific majority how to understand the impact of science, and especially medical science, on their lives. Take radiation. We all know that it can be harmful, and people like me, who spend their working lives irradiating patients, make great efforts to keep the doses used to a minimum. But we need to maintain a sense of proportion. There was a case recently of a man who spent weeks on a ventilator in an intensive care unit after a severe road traffic accident. His chances of survival were less than evens, but, thanks to the skill of the nursing and medical staff, he made a full recovery. His first action on going home?..he sued the hospital. Why? Because he had become aware that while he was unconscious, he had been subjected to a number of chest x-rays, and he was concerned that the radiation might have damaged his health. And it might have done, but the risk to health from a chest x-ray is tiny, unmeasurable, and without regular x-rays to monitor the condition of his lungs, he would almost certainly have died. It's all about balancing risk and benefit.

And then there are the 'side effects' of medicines. I'll let you in on a secret. There is no such thing as a side effect. Drugs are chemicals that are likely to have several effects on our bodies, only one of which will be the desired, therapeutic, one. A side effect is just an unwanted effect, in the same way that a weed is just a plant in the wrong place. Good medicine consists of choosing the right drug in the right dose, and balancing the possibility of these unwanted effects against the chance of cure.

All of which illustrates an uncomfortable fact that doctors seldom talk about in front of patients in case they frighten them. Medicine is a percentage game; we don't deal in certainty, in black and white, but in shades of grey. We play the odds in an informed way, hopefully ensuring that the investigation and treatment we prescribe has net benefit for the patient. But it is possible to get everything right, and still do harm to the patient. For the tabloids of course, every adverse outcome in medicine is a 'blunder' or a 'scandal', and occasionally they are right, but often it's just the laws of chance conspiring against patient and doctor.

Rightly or wrongly, doctors haven't always been completely open with patients about the risks of investigation and treatment, but that's all changing. Consent to treatment can only be truly 'informed' if patients are told of all the significant risks involved, and if we want them to make sense of this new information without being frightened witless, schools must devote less time to heating test tubes over bunsen burners and more to exploring the concept of relative risk. Our friends in the media could do with a refresher course, too.